WO2024254792A9

WO2024254792A9 - Power detection

Info

Publication number: WO2024254792A9
Application number: PCT/CN2023/100259
Authority: WO
Inventors: Md Arif HUSSAIN ANSARI; Theng Tee Yeo; Tao Yan
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2023-06-14
Filing date: 2023-06-14
Publication date: 2025-12-18
Anticipated expiration: 2025-12-14
Also published as: CN121058164A; WO2024254792A1

Abstract

This disclosure is directed to an electronic circuit, an electronic device, a transmitting apparatus and an electronic apparatus. The electronic circuit generally comprises a transformer and a coupler. The transformer comprises a primary coil and a secondary coil, wherein the primary coil receives a first signal from a power amplifier, and the secondary coil is magnetically coupled with the primary coil and outputs a second signal to an antenna. The coupler comprises a plurality of coupling paths for obtaining a forward power for the second signal. Each of the coupling paths is magnetically coupled with a part of the transformer to generate a voltage indicating the forward power for the second signal. The coupler is configured to be adjacent to and integrated within the transformer. According to the embodiments of the present disclosure, a desirable directional coupling without sacrificing chip area and insertion loss can be achieved at a wide isolation bandwidth.

Description

POWER DETECTION

FIELD

The present disclosure relates to a field of power detection, and specifically to an electronic circuit or an electronic device for detecting power, a transmitting apparatus and an electronic apparatus.

BACKGROUND

In various radio frequency applications such as mobile phones, Wi-Fi routers, and RF transceivers, directional couplers are increasingly important. For example, a directional coupler may be integrated at an output stage of a power amplifier (PA) in the transmitter chain. The power coupled to the directional coupler may be configured to sample, measure or detect the transmitting signal.

It is important to obtain accurate power detection, for example, the amplified transmitting power from the PA. With such an accurate detected power, it is possible to appropriately calibrate or optimize operation of a wireless transmitter or transceiver. Directional couplers have been adopted to obtain the accurate power by detecting coupled power to the directional couplers. In some conventional manners, a coupler may be positioned between a transformer, for example a Balun transformer, and an antenna. In these cases, the coupler is connected between a transformer and an antenna in a cascade manner. This configuration usually has a relatively large footprint and high signal loss.

SUMMARY

In general, example embodiments of the present disclosure propose an electronic circuit, an electronic device, a transmitting apparatus and an electronic apparatus for achieving directional coupling without sacrificing chip area and insertion loss.

In a first aspect, there is provided an electronic circuit. The electronic circuit comprises a transformer and a coupler. The transformer comprises a primary coil and a secondary coil. The primary coil is configured to receive a first signal from a power amplifier, and the secondary coil is magnetically coupled with the primary coil and configured to output a second signal to an antenna. The coupler may comprise a plurality of coupling paths, e.g., two, three or more coupling paths, which are magnetically coupled with a part of the transformer, e.g., with a part of the primary and/or secondary coils. The plurality of coupling paths are configured to selectively generate a voltage (e.g., a proportional voltage) indicating a forward power for the second signal on at least one of the plurality of coupling paths. By means of magnetic coupling, the coupling paths of the coupler may be integrated within the transformer in a more compact manner, so that any additional components between the amplifier and the antenna may be omitted, thereby reducing the chip area and eliminating the insertion loss caused by those components.

According to the present disclosure, the coupler may be configured to be adjacent to the transformer. By configuring the coupler in the vicinity of the transformer, the coupler is fully integrated into or within the transformer, so that power can be transferred directly from the transformer to the antenna, thereby eliminating any matching network between the transformer and the antenna, significantly reducing the required circuit footprint, and eliminating insertion loss, i.e., achieving zero insertion loss. Other electronic components such as coupling resistors or capacitors, and isolation resistors or capacitors, may be configured together with the coupler to achieve a more compact circuit design and a required matching network.

According to example implementations of the present disclosure, the coupling path may comprise an inductive coil (or trace) that is magnetically coupled to the primary and/or secondary coil and configured to generate a voltage (e.g., a proportional voltage) indicating the forward power for the second signal. As a part of the coupler, the inductive coil may be also in the vicinity of the transformer, and may be disposed at an arbitrarily position around the transformer, so as to produce a desirable forward power. With these implementations, the coils of the transformer and the coupler can be organized in a more compact manner, thus occupying less area without incurring insertion loss. Furthermore, a number of switching inductive coils enable a wide isolation bandwidth with each inductive coil operating on a separate or consecutive tuned frequency band.

In some example implementations, the coupling path may further comprise an isolation capacitor coupled between a first end of the inductive coil of the coupling path and a first terminal of the power amplifier (e.g., a positive output terminal of a differential power amplifier) . The coupling path may further comprise an isolation resistor coupled between the isolation capacitor and a ground terminal. With these implementations, by selecting or changing the parameter values of the isolation capacitor and the isolation resistor, the coupling and isolation factors of each of the coupling paths can be adjusted in a fast and convenient manner.

In some example implementations, the coupler may further comprise a coupling resistor common to the plurality of coupling paths. The coupling resistor is coupled between a second end of the inductive coil and the ground terminal, the second end being opposite to the first end. The coupling path may further comprise a coupling capacitor coupled between the second end of the inductive coil and the antenna. With these implementations, the coupling and isolation factors of each coupling path can be further adjusted in a fast and convenient manner by selecting or changing the parameter values of the coupling capacitor and the coupling resistor.

In some example implementations, the coupler may further comprise a switching network. The switching network is connected between the second end of the inductive coil and the coupling resistor. The switching network may be configured to be adjacent to the transformer accordingly. The switching network is further configured to selectively switch on one of the plurality of coupling paths with a control signal. It is understood that the switching network can also be configured to selectively switch on more of the plurality of coupling paths if desired according to a specification application. With these implementations, the isolation bandwidth can be selected flexibly according to specific applications. A coupled port is thus formed between the switching network and the coupling resistor. Since two or more inductive coils of the coupling paths are configured along with the switching network, the overall isolation bandwidth can be effectively broader than a single inductive coil in addition to avoiding additional chip area.

In some example implementations, the switching network may comprise a plurality of switches corresponding to the plurality of coupling paths and coupled between the coupling resistor and the plurality of coupling paths. An input terminal of each of the plurality of switches is connected to a corresponding second end of the inductive coil of the plurality of coupling paths, and an output terminal of each of the plurality of switches is connected to the coupled port. In an example implementation, the switch comprises a MOSFET. With these implementations, the switching network (e.g., a MOSFET based switching network) , together with the respective coupling capacitors, and isolation capacitors, maximizes the isolation bandwidth. In particular, the switching network, coupling capacitors, and isolation capacitors enable the electronic circuit to be configured as a circuit with a multi-isolation bandwidth in different frequency bands. Furthermore, since all the components of the coupler are integrated within the transformer, additional matching network after the switching network is avoided, which further reduces the chip area, because the area occupied by additional components are negligible as compared to the size of the transformer. Hence, the present disclosure can effectively achieve a wide isolation bandwidth without sacrificing area (effectively no additional area) and insertion loss (zero insertion loss) .

In some example implementations, the switching network could comprise of electronically controlled switching devices, such as MOSFETs, BJTs, HBTs, or any other switching devices. The switching devices could be of any mechanism, which could be fabricated on chip. The switching devices could be made of RF MEMS for better performance.

In some example implementations, the isolation resistor or the coupling resistor is a variable resistor. The coupling path may further comprise a shunt capacitor in parallel with the isolation resistor or the coupling resistor. Alternatively, or in additional to the isolation resistor or the coupling resistor, there may be an RLC (R-Resistor, L-Inductor, C-Capacitor) , RC or RL network at a port of the coupler (e.g., coupled port or isolation port) . With these implementations, by changing the parameter values of the respective coupling or isolation resistor, the coupling or isolation capacitor and/or inductors, the coupling and isolation factors of each of the plurality of coupling paths can be adjusted in a fast, reliable and convenient manner.

In some example implementations, one or more of the plurality of the inductive coils of the coupler are provided inside the transformer, outside the transformer, above the transformer, or below the transformer. With these implementations, the size of the electronic circuit may be made much smaller and it could be effectively used for ultra-wide isolation bandwidth or multi band operations.

In some example implementations, the inductive coil of the coupler is stacked with the part of the secondary coil or distributed around the vicinity of the part of the secondary coil. In an example implementation, the plurality of inductive coils may comprise a first inductive coil disposed around the vicinity of the part of the secondary coil, a second inductive coil disposed above the part of the secondary coil, and a third inductive coil disposed under the part of the secondary coil. With these implementations, the size of the electronic circuit may be made more compact and further reduce the required chip area.

In a second aspect, there is provided an electronic device, comprising a transformer and a coupler. The transformer is provided between a power amplifier and an antenna. The transformer comprises a primary coil coupled to the power amplifier and a secondary coil coupled to the antenna and magnetically coupled with the primary coil. The coupler is configured to be adjacent to the transformer. The coupler comprises a plurality of coupling paths configured to be adjacent to a part of the secondary coil.

In some example implementations, the coupling path may comprise an inductive coil or trace magnetically coupled to the transformer.

In some example implementations, the coupling path may further comprise an isolation capacitor coupled between a first end of the inductive coil and a first terminal (e.g., positive or source terminal) of the power amplifier, and an isolation resistor coupled between the isolation capacitor and a ground terminal.

In some example implementations, the coupler may further comprise a coupling resistor common to the plurality of coupling paths. The coupling resistor is coupled between a second end of the inductive coil and the ground terminal, the second end being opposite to the first end. The coupling path may further comprise a coupling capacitor coupled between the second end of the inductive coil and the antenna.

In some example implementations, the coupler may further comprise a switching network. The switching network is configured to be adjacent to the transformer and connected between the second end of the inductive coil and the coupling resistor, and configured to selectively switch on one or more of the plurality of coupling paths with a control signal. A coupled port is thus formed between the switching network and the coupling resistor.

In some example implementations, the switching network may comprise a plurality of switches corresponding to the plurality of coupling paths and coupled between the coupling resistor and the plurality of coupling paths. An input terminal of each of the plurality of switches is connected to a corresponding second end of the inductive coil of the plurality of coupling paths, and an output terminal of each of the plurality of switches is connected to the coupled port. In an example implementation, the switch comprises a MOSFET.

In some example implementations, the isolation resistor or the coupling resistor is a variable resistor, and the coupling path further comprises a shunt capacitor in parallel with the isolation resistor or the coupling resistor.

In some example implementations, one or more of a plurality of the inductive coils of the coupler are provided inside of the transformer, outside the transformer, above the transformer, or below the transformer.

In some example implementations, the inductive coil of the coupler is stacked with the part of the secondary coil or distributed around the vicinity of the part of the secondary coil. In an example implementation, the plurality of inductive coils may comprise a first inductive coil disposed around the vicinity of the part of the secondary coil, a second inductive coil disposed above the part of the secondary coil, and a third inductive coil disposed under the part of the secondary coil.

In a third aspect, there is provided a transmitting apparatus, comprising an antenna, and an electronic circuit according to the first aspect or an electronic device according to the second aspect, which is coupled to the antenna.

In a fourth aspect, there is provided an electronic apparatus comprising a transmitting apparatus according to the third aspect and a power supply, the power supply being configured to supply power to the transmitting apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the following detailed description with reference to the accompanying drawings, the above and other objectives, features and advantages of the example embodiments disclosed herein will become more comprehensible. In the drawings, several example embodiments disclosed herein will be illustrated in an exemplary and in a non-limiting manner, wherein:

Fig. 1 illustrates an example electronic device in which the electronic circuit in accordance with an example embodiment of the present disclosure may be implemented;

Fig. 2 illustrates a diagram of an electronic circuit in accordance with a related approach;

Fig. 3 illustrates an example layout of the electronic circuit shown in Fig. 2;

Fig. 4 illustrates a circuit diagram of an electronic circuit in accordance with an example embodiment of the present disclosure;

Fig. 5 illustrates an example layout of the example electronic circuit shown in Fig. 4;

Fig. 6 illustrates an example implementation of the example electronic circuit shown in Fig. 5, wherein the traces or coils of the electronic circuit are shown with layout representation;

Fig. 7 illustrates an example implementation of the example electronic circuit in accordance with another example embodiment of the present disclosure;

Fig. 8 illustrates an example implementation of the example electronic circuit in accordance with a further example embodiment of the present disclosure;

Fig. 9 illustrates an example implementation of the example electronic circuit in accordance with a further example embodiment of the present disclosure;

Fig. 10 illustrates an example implementation of the example electronic circuit in accordance with a further example embodiment of the present disclosure;

Fig. 11 illustrates an example implementation of the example electronic circuit in accordance with a further example embodiment of the present disclosure; and

Fig. 12 illustrates an example implementation of the example electronic circuit in accordance with a further example embodiment of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and to help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to apply such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It should be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

Fig. 1 illustrates an example electronic device 1 in which the electronic circuit in accordance with an example embodiment of the present disclosure may be implemented. As shown, the electronic device 1 generally includes a transceiver 11 and a power supply 12. The power supply 12 supplies power to the transceiver 11 to ensure the normal operation of the transceiver 11. The transceiver 11 includes, among other things, a power amplifier 111, an antenna 113 and an electronic circuit 112 coupled to the power amplifier 111 and the antenna 113. In an embodiment, the electronic circuit 112 may comprise a transformer, such as a Balun, and a coupler, such as a directional coupler. A signal may be transmitted from the power amplifier 111 to the antenna 113 via the electronic circuit 112. It is to be understood that the illustrated electronic device 1 is only illustrative without limiting scope of the disclosure.

As described above, the related configuration of coupler and transformer usually has a relative large footprint or size. Fig. 2 illustrates a diagram of an electronic circuit 20’ in accordance with a related directional coupler. As shown, the electronic circuit 20’ generally includes a power amplifier 21’, a transformer 22’, a coupler 23’ and an antenna 24’. The transformer 22’ may be implemented as a Balun in an example, and is coupled between the power amplifier 21’ and the antenna 24’ together with the coupler 23’. The transformer 22’ and the coupler 23’ thus are connected in a cascade manner.

The transformer 22’ includes a primary coil L₁’ and a secondary coil L₂’. The primary coil L₁’ is coupled to the power amplifier 21’ and is used in an example to receive a signal from the power amplifier 21’. The secondary coil L₂’ is magnetically coupled with the primary coil L₁’ to output a signal to the coupler 23’. The coupler 23’ is coupled between the secondary coil L₂’ and the antenna 24’, and includes a first coil L₃’ and a second coil L₄’. With the coupler 23’, an induced signal can be formed in the second coil L₄’ based on the signal transmitted through the first coil L₃’. Characteristics of the induced signal may thus represent the characteristics of the signal transmitted through the first coil L₃’, such as power of the amplified signal. A resistor Z_coup is coupled to the second coil L₄’ at a coupled port so as to detect the signal. Based on the signal, the transmitted power from power amplifier 21’ to the antenna 24’ can be determined accordingly.

Fig. 3 illustrates an example layout of the electronic circuit shown in Fig. 2. The transformer 32’ comprising the primary coil L₁’ and the secondary coil L₂’ is implemented as a coil assembly. The coupler 33’ comprising the first coil L₃’ and the second coil L₄’ is implemented as the other coil assembly. Thus, the electronic circuit 30’ generally includes two coil assemblies. Since the two coil assemblies are connected and implemented in a cascade manner, each coil assembly occupies an independent footprint. The overall footprint of the two coil assemblies is basically the sum of the two independent footprints, causing a relatively large overall footprint or area. Since the two coil assemblies occupy a relatively large area of the chip associated with the electronic circuit 30’, the chip has to include more space to accommodate the two coil assemblies. Therefore, it is difficult for the related chip to be miniaturized, limiting the application scenarios. Moreover, the first coil L₃’ provided between the secondary coil L₂’ and the antenna 34’ will incur insertion loss during the transmission of the signal.

To at least address the above issues in the current electronic circuit 20’, 30’, embodiments of the present disclosure propose new architectures. The electronic circuit according to the example embodiments of the present disclosure does not provide any component, such as a coil or coil assembly, between the transformer such as Balun and the antenna. Rather, it enables a direct connection between the transformer and the antenna. In this way, the overall footprint of the transformer and the coupler may be reduced. In addition, the insertion loss caused by the coil between the transformer and the antenna can be avoided.

The coupler implementation using electrically small trace enables area efficiency and improves isolation (in other term directivity) but it reduces the isolation bandwidth. Although, coupler implementation using single trace shows advantage but limited for wide-bandwidth applications. The electronic circuit according to the present disclosure adopts a plurality of coupling paths disposed in the vicinity of the transformer to detect the forward power respectively. The plurality of coupling paths are tuned to operate at multiple consecutive frequency-bands, which makes the present disclosure suitable for wide-band operation without sacrificing area and effectively zero insertion loss. In addition, the coupling paths in the present disclosure tuned to operate in the different frequency bands enable it for multi-band operation.

Example embodiments of the present disclosure will be described in more detail hereinafter with reference to Figs. 4 to 12. Fig. 4 illustrates a circuit diagram of an electronic circuit 40 in accordance with an example embodiment of the present disclosure. As shown in Fig. 4, the electronic circuit 40 generally includes a transformer 42 and a coupler 43. The transformer 42 is a Balun in an example, and includes a primary coil L₁ and a secondary coil L₂. The primary coil L₁ is coupled to a power amplifier 41, and is used to receive a first signal from the power amplifier 41. The secondary coil L₂ is magnetically coupled with the primary coil L₁, and is coupled to an antenna 44. The secondary coil L₂ outputs a second signal to the antenna 44.

As shown, the primary coil L₁ of the transformer 42 has a first input terminal PA+, and a second input terminal PA-. The primary coil L₁ is coupled between the first input terminal PA+ and the second input terminal PA-, and the first input terminal PA+ and the second input terminal PA-are coupled to a positive output terminal and a negative output terminal of a differential power amplifier 41, respectively. The secondary coil L₂ is coupled between an output terminal ANT and a reference terminal, for example a ground terminal GND, and the output terminal ANT is directly coupled to the antenna 44. The amplified signal generated by the power amplifier 41 may be tailored to an appropriate signal for the antenna with the transformer 42.

The coupler 43 is configured to be adjacent to the transformer 42, with their coils for example stacked or interleaved. The coupler 43 includes a plurality of coupling paths, e.g., two, three or more coupling paths. As shown, three coupling paths are each magnetically coupled with a part of the first coil L₁ and the secondary coil L₂. The plurality of coupling paths are configured to selectively generate a voltage indicating a forward power for the second signal from the transformer 42 on at least one of the plurality of coupling paths. In an example, one of the plurality of coupling paths is selected to generate the required voltage indicating the forward power.

By magnetically coupling, the coupling paths are coupled with a part of the transformer 42, the coupler may be spatially integrated within the transformer in a more compact manner, so that any additional components between the amplifier and the antenna may be omitted, thereby reducing the chip area and eliminating the insertion loss caused by those components. In additional, by configuring the coupler 43 in the vicinity of the transformer 42, the coupler 43 is spatially integrated into or within the transformer 42 in a plain view. Power thus can be transferred directly from the transformer 42 to the antenna 44, eliminating any component or matching network between the transformer 42 and the antenna 44, significantly reducing the required circuit footprint, and eliminating insertion loss, i.e., achieving zero insertion loss. Other electronic components such as coupling resistors or capacitors, and isolation resistors or capacitors, may be configured together with the coupler 43 to achieve a more compact circuit design and a matched network.

The coupling paths are multiple inductive coils L_C1, L_C2, ……L_CN that are mutually coupled to the transformer 42 and configured to generate a voltage indicating the forward power for the second signal. The inductive coils L_C1, L_C2, ……L_CN may be implemented for example as traces, such as metal traces. As shown in an example of Fig. 5, three coupling paths comprise three inductive coils L_C1, L_C2, and L_C3, respectively. As a part of the coupler 43, the inductive coil of each coupling path is also in the vicinity of the transformer 42, and may be disposed at an arbitrarily position around the secondary coil L₂ of the transformer 42, so as to produce a desirable forward power. The traces or coils of the transformer 42 and the coupler 43 can be organized in a more compact manner, thus occupying less area without incurring insertion loss. Furthermore, a number of the inductive coils enable a wide isolation bandwidth with each inductive coil of the coupler operating on a separate frequency band.

The coupling path may further comprise an isolation capacitor C_M21, C_M22, ……C_M2N. The isolation capacitor C_M21, C_M22, ……C_M2N is coupled between a first end of a corresponding inductive coil L_C1, L_C2, ……L_CN of the coupling path and a positive output terminal of the power amplifier 41 to at least partially determine a coupling factor of the coupling path, which is an important factor to evaluate the performance of the coupling path. Likewise, the inductive coils L_C1, L_C2, ……L_CN may be implemented as traces, such as metal traces. In the illustrated embodiment, the coupling path may further comprise an isolation resistor Z_ISOL. The isolation resistor Z_ISOL may be coupled between the isolation capacitor C_M21, C_M22, ……C_M2N and a ground terminal GND. Parameter values of the isolation capacitor and the isolation resistor can be variable in an embodiment, so that they can be selected to adjust the coupling factor of each of the coupling paths in a fast and convenient manner. Likewise, an isolation factor of the coupling path may be determined in a similar manner, and can be adjusted accordingly. It is to be understood that the parameter values of the isolation capacitor and the isolation resistor can be fixed or partially fixed in some embodiments.

The coupler 43 may further comprise a coupling resistor Z_COUP common to the plurality of coupling paths. The coupling resistor Z_COUP is coupled between a second end of the inductive coil L_C1, L_C2, ……L_CN and the ground terminal GND, and the second end is opposite to the first end. The plurality of coupling paths may further comprise a coupling capacitor C_M11, C_M12, ……C_M1N. The coupling capacitor C_M11, C_M12, ……C_M1N is coupled between the second end of the inductive coil L_C1, L_C2, ……L_CN and the antenna 44. The forward power may be detected at the coupling resistor Z_COUP, which forms a coupled port 47. The combination of the isolation capacitors C_M21, C_M22, ……C_M2N and the coupling capacitors C_M11, C_M12, ……C_M1N along with the isolation resistors Z_ISOL and the coupling resistor Z_COUP can determine an amount of the forward power coupled to the coupling resistor Z_COUP (coupled port) and the isolation resistor Z_ISOL (isolated port) .

As discussed above, the coupling and isolation factors of each coupling path can be further adjusted in a fast and convenient manner by selecting or changing the parameter values of the respective coupling capacitors and the coupling resistor. Furthermore, by providing the coupling resistor Z_COUP to the plurality of coupling paths, a desired coupling with good isolation between the antenna and the forward coupled port can be achieved, thus improving the directivity of each of the coupling paths, and reducing the required footprint. In particular, only forward power will be coupled and there is no reflected power. It is to be understood that the coupling resistor Z_COUP or the isolation resistor Z_ISOL may also be implemented with other forms of an impedance.

The coupler 43 may further comprise a switching network 46. The switching network 46 is also configured to be adjacent to the transformer 42. The switching network 46 is connected between the second end of the inductive coil L_C1, L_C2, ……L_CN and the coupling resistor Z_COUP. The switching network 46 can be configured to selectively switch on, with a control signal, one or more of the plurality of coupling paths, e.g., one of the inductive coil L_C1, L_C2, ……L_CN. With the switching network 46, the isolation bandwidth can be selected flexibly according to specific applications. Correspondingly, the coupled port is formed between the switching network 46 and the coupling resistor Z_COUP. As mentioned above, the inductive coil, L_C1, L_C2, ……L_CN , which is a small coupling implementation, narrows down the isolation bandwidth. In order to maximize the isolation bandwidth, the present disclosure utilizes two or more inductive coils along with the switching network 46. Therefore, the overall isolation bandwidth can be effectively broader than a single inductive coil in addition to avoiding additional chip area.

In the illustrated embodiment, the switching network 46 may comprise a plurality of switches corresponding to the plurality of coupling paths and coupled between the coupling resistor Z_COUP and the plurality of coupling paths. The switch may comprise a MOSFET in an embodiment. Thus, the switching network 46 may be configured as a MOSFET based switching network, which comprise a plurality of MOSFET switches corresponding to the plurality of coupling paths. An input terminal of each of the plurality of switches is connected to a corresponding second end of the inductive coil of the plurality of coupling paths, and an output terminal of each of the plurality of MOSFET switches is connected to the coupled port 47. Therefore, the switching network 46, together with the respective coupling capacitors, and isolation capacitors, maximizes the overall isolation bandwidth. In particular, the switching network, coupling capacitors, and isolation capacitors enable the electronic circuit 40 to be configured as a circuit with a multi-isolation bandwidth in different frequency bands. In other words, each of the plurality of the coupling paths can be designed to have a specific inductive trace or coil so as to be suitable for a targeted frequency band, and thus all of the coupling paths constitute a broadened overall bandwidth in different frequency bands depending on the number of the inductive coils of the coupling paths. Furthermore, since all the components of the coupler 43 are integrated with the transformer 42, additional matching network after the switching network 46 is avoided, which further reduces the chip area, because the area occupied by additional components are negligible as compared to the size of the transformer 42. Hence, the present disclosure can effectively achieve a wide isolation bandwidth without sacrificing area (effectively no additional area) and insertion loss (zero insertion loss) .

In the illustrated embodiment, a simplified switching network 46, due to the configuration of the present disclosure, eradicates the requirement for additional matching network. In particular, the present disclosure enables the layout of the components, e.g., the MOSFET based switching network 46, to be simplified and makes it less parasitic prone such that an intensive optimization is not needed after connecting all capacitors, resistors, and switches. The placement of isolation capacitors and coupling capacitors may be wisely choose to make the layout scalable for multiband or ultrawide band applications. The operational bandwidth of electronic circuit 40 of the present disclosure is limited by the bandwidth of the transformer 42. The chip area of the coupler 43 or the coupling paths integrated with the transformer 42 is limited by the chip area of the transformer 42. The additional area of the coupler 43 or the coupling paths is negligible (effectively zero) . The insertion loss is limited by only the insertion loss of the transformer 42. The insertion loss due to coupler integration is negligible (almost zero) .

In Fig. 5, the isolation resistor Z_ISOL or the coupling resistor Z_COUP constitutes a fixed isolation or coupling impedance. It is understood that the isolation resistor Z_ISOL or the coupling resistor Z_COUP may be a variable resistor that constitutes a variable isolation or coupling impedance. The coupling paths may further comprise a shunt capacitor in parallel with the isolation resistor or the coupling resistor, e.g., shunt capacitors C_M31, C_M32, C_M33 as shown in Fig. 7, thereby tuning the isolation resonance and bandwidth. Alternatively, or in additional to the isolation resistor or the coupling resistor, there may be an RLC (R-Resistor, L-Inductor, C-Capacitor) , RC or RL network at a port of the coupler (e.g., coupled port or isolation port) . By changing the parameter values of the respective coupling or isolation resistor, the coupling or isolation capacitor and/or inductors, the coupling and isolation factors of each of the plurality of coupling paths can be adjusted in a fast, reliable and convenient manner.

In the illustrated embodiment, one or more of the plurality of the inductive coils L_C1, L_C2, ……L_CN of the coupler 43 may be provided inside the transformer, outside the transformer, above the transformer, or below the transformer, so long as the inductive coils are disposed adjacent to the transformer. With the placement according to the present disclosure, the size of the electronic circuit 40 may be made much smaller.

Fig. 5 illustrates an oblique view of an example layout of the example electronic circuit shown in Fig. 4, and Fig. 6 illustrates an example implementation of the example electronic circuit shown in Fig. 5, which includes an example configuration of the electronic circuit, an example layout and its cross-section, and an example layout implemented in a CMOS process. Fig. 5 and Fig. 6 are intended to illustrate example layout and the implementations of the traces or coils. Thus, description for the components other than traces or coils will be omitted here for brevity. In an embodiment as shown in Fig. 5, the primary coil L₁ is formed inside the secondary coil L₂. In another embodiment, the primary coil L₁ may be formed outside the secondary coil L₂. There is no restriction to the position of the primary coil L₁ and the secondary coil L₂, as long as they can operate to achieve function of a transformer. As shown in Fig. 6, the coupling capacitors C_M11 to C_M1N, the switching network 46, the isolation capacitors C_M21 to C_M2N, the coupling resistor Z_COUP and the isolation resistors Z_ISOL are all configured in the vicinity of the transformer 42, e.g., in the vicinity of the secondary coil L₂, within the footprint of the transformer 42. The secondary coil L₂ of the transformer 42 is in a direct connection to the antenna 44. In other words, no additional components are disposed between the transformer 42 and the antenna 44. As a result, there will be no insert loss in the electronic circuit 40.

An inductive trace/arm or coil L_C1, L_C2, ……L_CN of the coupling path is provided adjacent to a part of the secondary coil L₂ to magnetically couple with said part. In Fig. 5, the inductive coils L_C1, L_C2 and L_C3 are positioned outside the secondary coil L₂. Alternatively, the inductive coils L_C1, L_C2 and L_C3 may be positioned inside, above or below the secondary coil L₂. In addition, a plurality of the inductive coils of the coupler may be stacked with each other in different layers, stacked with the part of the secondary coil L₂, or distributed around the vicinity of the part of the secondary coil L₂. In Fig. 5, three inductive coils L_C1, L_C2 and L_C3 are stacked together with each other in different layers. It is noted that the three inductive coils L_C1, L_C2 and L_C3 are clearly depicted in the oblique view of Fig. 5, and thus it is understood that only the uppermost inductive coil can be seen in a plan view (see Fig. 6) . In an example implementation as shown in Fig. 6, the plurality of coupling paths comprise three inductive coils L_C1, L_C2 and L_C3, respectively, with a first inductive coil disposed around the vicinity of a part of the secondary coil L₂, a second inductive coil disposed above the part of the secondary coil L₂, and a third inductive coil disposed under the part of the secondary coil L₂. The three inductive coils L_C1, L_C2 and L_C3 are stacked with each other. With this configuration, the size of the electronic circuit may be made more compact and further reduce the required chip area. It is also understood that the inductive coils can be distributed in the vicinity of the secondary coil L₂ or transformer at any arbitrary positions according to a specification application scenario. Although Fig. 6 illustrates a specific stack of three inductive coils L_C1, L_C2 and L_C3, they can be positioned in other manners. For example, in an embodiment, the inductive coil L_C2 may be positioned outside the secondary coil L₂, and the inductive coils L_C1 and L_C3 may be positioned right above and below the secondary coil L₂, respectively.

With reference to Fig. 5, the three inductive coils L_C1 to L_C3 of the coupler are located outside the secondary coil L₂ of the transformer 42, and the secondary coil L₂ of the transformer 42 is located outside the primary coil L₁. In other words, the coils L₁ and L₂ of the transformer 42 are positioned in a concentric arrangement, and the coils L_C1 to L_C3 in the coupling paths of the coupler are positioned to surround at least a part of the secondary coil L₂ of the transformer 42, e.g., along one side of the transformer. Thus, the coils L₁ and L₂ of the transformer 42 and the coupler 43 are organized in a more compact manner, occupying less area. Therefore, no additional chip area is required and the size of the associated chip can be made smaller to adapt to more scenarios.

It is to be understood that the spatial locations of the inductive coils L_C1 to L_C3 and the secondary coil L₂ are only illustrative without limiting scope of the disclosure. They can be adjusted according to the spatial considerations of the actual applications, as long as they are close enough to induce power from the secondary coil L₂. For example, in other example embodiments, the locations of the inductive coils L_C1 to L_C3 in the coupling paths of the coupler 43 may be designed to be inside the transformer 42, along one side or both sides thereof, as shown in Fig. 8 and Fig. 9, respectively. Alternatively, the inductive coils L_C1 to L_C3 in the coupling paths of the coupler 43 may be positioned with one part thereof to be inside the transformer 42, and with the other part thereof to be outside of the transformer 42, as shown in Fig. 10. In other words, the coils L₁ and L₂ of the transformer 42 are sandwiched between the coils L_C1 to L_C3 of the coupler 43. Alternatively, the inductive coils L_C1 to L_C3 in the coupling paths of the coupler 43 may be positioned completely surrounding the transformer 42 in a closing manner, as shown in Fig. 11. In other words, the coils L₁ and L₂ of the transformer 42 are enclosed by the coils L_C1 to L_C3 of the coupler 43. Alternatively, the inductive coils L_C1 to L_C3 in the coupling paths of the coupler 43 may be positioned between the primary coil L₁ and the secondary coil L₂ in an interleaved manner, as shown in Fig. 12.

According to the example embodiments described above, each coupling path of the coupler is provided for a specific forward power detection, which operates at a specific bandwidth of a frequency band. By increasing the number of coupling paths with corresponding number of inductive coils based on a specific application scenario, the overall isolation bandwidth can be as wide as desired. In the illustrated embodiment, three inductive coils are used together with the switching network for satisfying the bandwidth requirement of 5GHz WI-FI band. In particular, one inductive coil or arm of the coupler may correspond to a specific frequency band, which usually covers a relatively narrow band such as a few hundred MHz, e.g., around 300 MHz. Accordingly, three inductive coils of the coupler may cover the entire band from 5GHz to 6GHz. Simulation results of S-parameters and Harmonic Balance according to the present disclosure show a desirable coupling ratio, coupling error and flatness/variation of VSWR. For example, the VSWR is shown to be better than 1: 3, which is a fair requirement for the antenna. It is to be understood that the electronic circuit according to the present disclosure may be adapted to frequency bands other than 5GHz by means of choosing and designing an appropriate number of inductive coils of the coupler along with a corresponding switching network.

With the configuration of the electronic circuit of the present disclosure, the forward power of the second signal to the antenna can be determined accurately. In this way, example embodiments according to the present disclosure can be used to analyze the load impedance, which can be further used for improve power calibration accuracy, load tuning, etc. By detecting powers of the second signal, the reliability of power detection can be improved and eventually the accuracy of power detection and calibration can be improved accordingly, without introducing any insertion loss and/or sacrificing the chip area.

In example implementations, the coils according to the present disclosure may be implemented in a shape of a part of a polygon, e.g., as shown in Fig. 6. This is only for illustration without limiting scope of the present disclosure. Other shapes are possible, as long as they can generate induced signals. In addition, the coils are formed in a plain stripe, and this is also illustrative only.

It is to be understood that even though the above embodiments are described by using directional coupler as an example scenario, it is readily envisaged that this is only illustrative, rather than restrictive. The electronic circuit according to the present disclosure may be used in other scenarios.

With various placements of the capacitors and resistors, the parameters of the capacitors and the resistors may be similar or different among different placements, which may depend on different requirement of the users. For example, the parameter value of the isolation capacitor C_M2 in the embodiment as shown in Fig. 4 is different from that of the isolation capacitor C_M2 in the embodiment as shown in Fig. 7, or the value of the isolation resistor Z_ISOL in the embodiment as shown in Fig. 4 is different from that as shown in Fig. 7. In this way, the user may envisage a variety of placements of capacitors and resistors to achieve the intended purpose. In this way, by changing the parameter values of the specific devices, the coupling or isolation factor of each of the plurality of coupling paths can be adjusted in a fast and convenient manner. It is to be understood that the specific placements as shown in Figs. 4-12 are just a few examples, and they are not limited to embodiments of the present disclosure.

Example embodiments of the present disclosure further relate to a transmitting apparatus. The transmitting apparatus includes an antenna and an electronic circuit coupled to the antenna. The electronic circuit may be any electronic circuit described above. The transmitting apparatus may also include a power amplifier, a coupler, an antenna and the electronic circuit may be coupled between the antenna and the power amplifier.

Example embodiments of the present disclosure also relate to an electronic apparatus. The electronic apparatus includes a transmitting apparatus described above and a power supply configured to supply power to the transmitting apparatus.

Compared with the existing solutions of electronic circuit, the embodiments according to the present disclosure enable a desired directional or bi-directional power detection without sacrificing chip area and insertion loss. Therefore, a miniaturized coupler with electrically smaller size can be achieved.

While several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in language specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

An electronic circuit, comprising:

a transformer comprising:

a primary coil configured to receive a first signal from a power amplifier; and

a secondary coil magnetically coupled with the primary coil and configured to output a second signal to an antenna; and

a coupler comprising:

a plurality of coupling paths, magnetically coupled with a part of the transformer, and configured to selectively generate a voltage indicating a forward power for the second signal on at least one of the plurality of coupling paths.
The electronic circuit of Claim 1, wherein the coupling path comprises an inductive coil magnetically coupled to the part of the transformer and configured to generate a voltage indicating the forward power for the second signal.
The electronic circuit of Claim 2, wherein the coupling path further comprises:

an isolation capacitor coupled between a first end of the inductive coil and a first terminal of the power amplifier, and

an isolation resistor coupled between the isolation capacitor and a ground terminal.
The electronic circuit of Claim 3, wherein the coupler further comprises a coupling resistor common to the plurality of coupling paths, the coupling resistor being coupled between a second end of the inductive coil and the ground terminal, the second end being opposite to the first end;

wherein the coupling path further comprises a coupling capacitor coupled between the second end of the inductive coil and the antenna.
The electronic circuit of Claim 4, the coupler further comprises:

a switching network connected between the second end of the inductive coil through switch and the coupling resistor, the switching network configured to selectively switch on one of the plurality of coupling paths with a control signal.
The electronic circuit of Claim 5, wherein the switching network comprises a plurality of switching devices corresponding to the plurality of coupling paths and coupled between the coupling resistor and the plurality of coupling paths.
The electronic circuit of any of Claims 3-6, wherein the isolation resistor or the coupling resistor is a variable resistor, and the coupling path further comprises a shunt capacitor in parallel with the isolation resistor or the coupling resistor.
The electronic circuit of any of Claims 1-6, wherein one or more of the plurality of the inductive coils of the coupler are provided inside the transformer, outside the transformer, above the transformer, or below the transformer.
The electronic circuit of any of Claims 2-6, wherein the inductive coil of the coupler is stacked with the part of the secondary coil or distributed around the vicinity of the part of the secondary coil.
The electronic circuit of any of Claims 2-6, wherein a plurality of inductive coils comprise:

a first inductive coil, disposed around the vicinity of the part of the secondary coil;

a second inductive coil, disposed above the part of the secondary coil; and

a third inductive coil, disposed under the part of the secondary coil.
An electronic device, comprising:

a transformer provided between a power amplifier and an antenna, the transformer comprising:

a primary coil coupled to the power amplifier; and

a secondary coil coupled to the antenna and magnetically coupled with the primary coil; and

a coupler configured to be adjacent to the transformer, comprising:

a plurality of coupling paths, configured to be adjacent to a part of thetransformer.
The electronic device of Claim 11, wherein the coupling path comprises an inductive coil magnetically coupled to the transformer.
The electronic device of Claim 12, wherein the coupling path further comprises:

an isolation capacitor coupled between a first end of the inductive coil and a first terminal of the power amplifier, and

an isolation resistor coupled between the isolation capacitor and a ground terminal.
The electronic device of Claim 13, wherein the coupler further comprises a coupling resistor common to the plurality of coupling paths, the coupling resistor being coupled between a second end of the inductive coil and the ground terminal, the second end being opposite to the first end;

wherein the coupling path further comprises a coupling capacitor coupled between the second end of the inductive coil and the antenna.
The electronic device of Claim 14, the coupler further comprises:

a switching network, configured to be adjacent to the transformer and connected between the second end of the inductive coil through switch and the coupling resistor.
The electronic device of Claim 15, wherein the switching network comprises a plurality of switching devices corresponding to the plurality of coupling paths and coupled between the coupling resistor and the plurality of coupling paths.
The electronic device of any of Claims 13-16, wherein the isolation resistor or the coupling resistor is a variable resistor, and the coupling path further comprises a shunt capacitor in parallel with the isolation resistor or the coupling resistor.
The electronic device of any of Claims 11-16, wherein one or more of a plurality of the inductive coils of the coupler are provided inside the transformer, outside the transformer, above the transformer, or below the transformer.
The electronic device of any of Claims 12-16, wherein the inductive coil of the coupler is stacked with the part of the secondary coil or or distributed around the vicinity of the part of the secondary coil.
The electronic circuit of any of Claims 12-16, wherein a plurality of inductive coils comprise:

a first inductive coil, disposed around the vicinity of the part of the secondary coil;

a second inductive coil, disposed above the part of the secondary coil; and

a third inductive coil, disposed under the part of the secondary coil.
A transmitting apparatus, comprising:

an antenna; and

an electronic circuit of any of Claims 1-10 or an electronic device of any of Claims 11-20, coupled to the antenna.
An electronic apparatus, comprising:

a transmitting apparatus of Claim 21; and

a power supply configured to supply power to the transmitting apparatus.